In the formation of glassware it has been common practice to form a blank, or parison, in a parison molding portion of the glassware molding machine, to automatically transfer the parison to a blow molding portion of the glassware molding machine, and then to blow mold the parison into conformity to a blow mold.
In the parison molding portion of the glassware molding machine, a gob of molten glass is deposited into the parison mold; and a parison plunger is pressed into the parison mold, forcing the gob of glass into a parison that has the combined shape of the neck ring, the finish guide ring, the parison mold, and the parison plunger.
The parison mold portion of the glassware molding machine includes a neck ring that is constructed of two neck ring halves, and that forms the finish portion, or threaded neck, of the parison.
It is this finish portion, or threaded neck, of the parison that is used in the blow molding portion of the glassware molding machine to hold the parison as the parison is blow molded to the final configuration of the glassware; and this same finish portion becomes the threaded neck of the completed container.
Since the finish portion, or threaded neck, of the parison is used to hold the parison for blow molding, the finish portion must be cool enough to have the physical properties that will enable it to withstand the blow molding process and still retain dimensional integrity for the completed container; and yet, the temperature of the parison must be sufficiently high to provide a viscosity that will blow mold.
Thus, it has been a problem to provide cooling for the neck ring that will provide mechanical strength and dimensional integrity in the finish portion of the parison while maintaining the remainder of the parison at a temperature that is sufficiently high to allow blow molding.
For a number of years the prior art has dealt with sundry means for cooling various components that mold glassware. The current state of art may best be shown, for example, in U.S. Pat. No. 3,024,671 by Abbott et al., in which internal cooling means is provided for glass molding surfaces. Although the patent discloses that cooling air currents may be used by allowing their passage through various components including ring arms, it has been found in actual practice that such methods fall short in providing an effective cooling process.
Also related to the subject invention is U.S. Pat. No. 3,015,911 to Payne, the patent disclosing a particular cooling scheme for forming neck finishes on glass containers. However, this patent deals with the blow molding side and does not deal with the blank or parison side of the glass forming operation.
The art for dealing with the problem of adequately cooling the neck ring for parison mold has been advanced by patent applications Ser. No. 06/683,450 filed Dec. 19, 1984, and Ser. No. 06/719,381 filed Apr. 2, 1985, of common assignee.
In the aforesaid patent application of common inventorship entity and common assignee, compressed air is forced through a plurality of vertically disposed and circumferentially spaced holes in the neck ring, in the finish ring, and in the parison mold.
Typically, a glassware molding machine will include six or more sections; and each section includes a section box, a parison mold portion that is disposed above the section box, and a blow mold portion that also is disposed above the section box.
It has been common practice to provide a supply of air to each section box. The source of this air has been a large centrifugal blower, or fan, and an electric motor. Typically one such motorized fan has supplied air to a fan box or duct; and this fan box has supplied air to each section box.
Air in the section boxes has been used to provide cooling for the external surfaces of the blow mold, the parison mold, and the neck ring. In addition the air in the section box has been exhausted through a perforated dead plate. Optionally, there may be provided an overhead cooling means positioned above each blow mold for directing supplemental cooling air to the containers as well as to the neck rings and each blow mold. Glassware that is removed from the blow molding section of the glassware molding machine is placed on the dead plate immediately upon being removed from the blow mold and receives initial cooling thereupon by the flow of fan air from the section box.
The present patent application advances the art of molding glassware by providing apparatus and method for cooling the neck ring, the finish ring, and the parison mold by use of this fan air that is provided to the fan box, and to each section box, by a motorized fan.
By utilizing fan air from the section box for cooling the neck ring and the parison mold, the expense of providing compresssed air for these cooling functions is eliminated. This reduction in cost includes both the cost of electrical power, which has become a significant cost factor in producing glassware of recent years, and the cost of providing and of maintaining an air compressor.
In addition, in a preferred embodiment and method, the present invention utilizes air being exhausted from cooling passages in the parison plunger to control the temperature of the air in the section box.
It is a principal object of the present invention to provide apparatus and method for using fan air from the section box of an individual section glassware molding machine for cooling the neck ring, the finish ring, and the parison mold.
It is an object to provide apparatus and method for controlling the flow of fan air through the neck ring, finish ring, and parison mold, and thereby to provide optimum cooling and to achieve an increase in productivity.
It is an object of the present invention to reduce the cost of molding glassware by utilizing air presently available for cooling processes formerly achieved only at the expense of providing compressed air.
It is another object of the present invention to reduce national dependence upon imported oil by reducing the energy requirements of glassware molding operations.
It is a further object of the present invention to provide means for separating cooling air that is exhausting from the parison plunger from fan air that is being supplied to the neck ring from the section box.
It is still a further object to control the temperature of fan air so that consistent cooling of the neck ring, the finish ring, and the parison mold are achieved regardless of changes in ambient temperature.
Finally, it is an object of the present invention to utilize the thermal energy of air being exhausted from the parison plunger for maintaining fan air in the section box at a substantially constant temperature regardless of changes in the ambient temperature.